Birds in Flight Sculpture Restoration
Birds in Flight, by Jac T. Bowen, is a static sculpture formed from steel and copper-alloy plates. Located at the entrance to the Wornall Homestead, the artwork serves as a welcome to the well-known Kansas City neighborhood. Twenty years after its installation, the home owners' association began noticing signs of deterioration and contacted Zahner to assist.
The Zahner team fabricated a new framework to replace the original steel understructure. Instead of using the existing (and corrosive) steel pipe, Zahner manufactured new structural components in stainless steel, eliminating the possibility of deterioration. The new structure was re-clad in its original, freshly cleaned copper-alloy plates.
"Patina" is an oxidized layer which develops naturally on the surface of many metals. In many cases, this mineralized surface will protect the surface from further corrosion while providing unique colors and textures on the metal surface. This is a naturally occurring phenomenon for many metal alloys. The process can take many years to fully develop. Depending on the atmospheric conditions, the results of this oxidization process can be visually difficult to predict. Moisture, air, sun, as well as salt and pollutants each have a powerful effect. In addition, factors such as how the metal is stored and produced at the mill, and how it is cleaned and prepared can have striking effects on the final visual surface appearance.While the patination process is predictable, sometimes the end result will surprise and delight. This is because small shifts in the atmosphere can have large effects on how the patina colors reveal themselves.
Diagnosing Sculptural Repair for the Jac T. Bowen Sculpture
Galvanic corrosion, which occurs when two or more dissimilar metals encounter one another, is a common cause of metal deterioration.
Birds in Flight exhibited extensive galvanic corrosion and weathering. Over time, the hammered copper plates reacted with the painted steel support structure causing widespread rust. Although the steel structure was painted, scratches within the paint coating affected the electrochemical coupling, accelerating corrosion and weakening the steel. The weakened structure began to sag and lose its shape in reaction to wind force, gravity, and occasional snow and ice loads.
Repairing and Restoring the Sculpture
Once the cause of deterioration was identified, Zahner carefully de-installed the sculpture, transporting it to the Zahner shop.
Once there, each part was carefully disassembled, cleaned, and repaired, if required. Working from photographs, Zahner artisans reassembled the existing and newly created components, remaining true to the artist’s original intent.